A convertible version of the all-new Jaguar XK supercar has been announced at the Frankfurt Motor Show.

Designed alongside the ultra-lightweight XK Coupe, which made its world debut at the show on Tuesday, the convertible uses the same advanced aluminium body structure to achieve high levels of rigidity while minimising weight.

Weighing in at just 1.6 tons, the new convertible is lighter than both its predecessor - the XK8 Convertible - and rivals such as the Mercedes SL.

Powered by a 300bhp, 4.2-litre V8 engine and with sequential shift, steeringwheel mounted gearchange controls, the convertible has a 0-60mph acceleration time of six seconds and a top speed electronically restricted to 155mph - almost identical to the XK Coupe. The hood on the convertible is made of triplelined fabric designed to provide plenty of noise insulation.

It can be powered up or down in less than 18 seconds and stows fully out of sight beneath an aluminium tonneau cover in front of the boot.

A roll-over protection system comprising two aluminium hoops that deploy in milliseconds in the event of an accident is standard equipment, as is Jaguar's groundbreaking pedestrian crash safety "exploding bonnet" cushion which was also announced at Frankfurt.

" The all- new XK was designed from the outset to be a beautiful convertible," says Jaguar design director Ian Callum. "It is a statement of Jaguar design, elegant as well as powerful with the performance to match its looks."